Firearm



Aug. '22, 1944.' l c. c. LooMls 2,356,256"

FIREARM Filed May 161 1942 INVENTOR Krew/'d (C500/m15' BY W/wl, f

AGENT Patented Aug. 22, V1944- FIREARM Crawford C. Loomis, Ilion, N. Y., assignor to Remington Arms Company, Inc., Bridgeport, Conn., a corporation of Delaware Application May 16, 1942, Serial No. 443,272

4 Claims.

This invention relates in general to firearms, and, particularly to improvements in bolt-action firearms of the rimre type.

It is an object of this invention to provide means for reducing burst cartridge heads in rimire guns. A further object is to provide a gas escape port in the firearm receiver for preventing the hazards which normally accompany burst heads.

Other objects, features, and advantages of the invention will be discovered in the following detailed description and drawing of one form of apparatus for practicing the` invention.

In the drawing:

Fig. 1 shows a side elevation of a bolt-action rimre firearm adapted to use with the present invention.

Fig. 2 is a fragmentary sectional side elevation between lines 2-2 of Fig. 1.

Fig. 3 is an end elevation on line 3-3 of Fig. 2.

Fig. 4 is a perspective view of the head end of the bolt.

Referring to the drawing, the rearm shown is a rie of the rimre `.bolt-action type comprising a :barrel IQ, a receiver II having an insert I2 and a substantially cylindrical bolt-receiving portion apertured as at I3 to provide a shell ejection opening. The Ibolt Id is reciprocated in the receiver Il in the usual manner by operating the bolt handle (not shown) from its retracted or breech-open position to its forward breech-closing position and is provided with the usual cartridge extractors I5.

Other details in the construction and operation of the firearm including the breech bolt, ring mechanism and features of the receiver are more fully shown and described in the copending application of K. J. Lowe, Serial No. 306,457, led November 28, 1939.

The barrel IIE, as shown in more detail in Fig. 2, is secured at its chamber end in the end of the receiver II by a pair of pins I'I which are engaged in a set of oppositely disposed semicircular grooves I8 formed in the adjacent surfaces of the barrel I and receiver insert I2, the latter comprising, in this instance, a cartridge support and guide member for a singleshot type firearm.

The barrel chamber I9 is of Well known construction and comprises a bore at the rear of the barrel of slightly greater diameter than the barrel bore 29 and adapted to chamber a cartridge shell.

A recess or counterlcore 2| is provided in the end of the chamber, the recess being substantially equal in diameter to the diameter of a cartridge rim so as to form a' supporting surface for the periphery of the rim of a cartridge when the latter is pushed into the chamber. The seat of the counterbore 2| is preferably characterized by sloping or curved shoulders 22, as shown in Fig. 2, adapted to lconform to the pro-file of the cartridge rim and to form, thus, an annular firing anvil. 33 are the usual recesses formed in the end of the chamber for accommodating the cartridge extractors I5.

An annulus 24 is provided at the end of the assembled :barrel and receiver and is formed by turning down the exterior of the barrel at its chamber end somewhat in the shape of a tapered nozzle so that the end portion of the barrel is of reduced external ydiameter as indicated at 23 in Figs. 2 and 3. Thus, when the chamber end of the barrel is assembled in the receiver II and receiver insert I2, as aforesaid, the reduced portion 23 of the barrel forms, in conjunction with the inside wall of the receiver, an annulus 24 circumscribing the end of the barrel.

A gas port or vent is formed substantially centrally in the receiver insert I2 and comprises a downwardly and forwardly directed drilled hole 25 which communicates at its upper end with the annulus 2d and is open at its lower end to permit gases or sparks to escape from the annulus at a point remote from the shooters eyes.

It will be clear that the annulus 24 is open to the atmosphere whenever the bolt I4 is retracted from its breech-closing position. However, when the lbolt is advanced and locked in chamber-closing position and the gun is ready for ring, the annulus 24 is closed by the prox- 4imity of the bolt head 2B and thee only outlet for gases which may accumulate in the closed annulus 2d due to a burst cartridge head will be through the escape port 25.

It will be appreciated .by those familiar with firearms that the danger of injuring the shooters face and eyes, due to escaping gas or sparks occasioned by cartridge head bursts or other inadvertent explosions, is a real one and one which heretofore made the firing of many types of guns extremely hazardous.

The present embodiment provides a port 25 for the hot gases and sparks so that these dangerous elements are safely conducted away from the shooters face. It will be evident, therefore, that lthe closed passage or annulus 2li and its gas escape port 25 constitute a safety feature which is a useful improvement over other types of firearms.

As shown in Fig. 4, the bolt I4 is of well known construction being substantially cylindrical and provided with a longitudinal ring pin passage 21 drilled in the upper part of the bolt eccentric to the longitudinal axis thereof. Through this passage is projectable the iiring pin which comprises a plunger 28 provided with a substantially wedge-shaped firing pin point 29 and having capacityfor reciprocation in the passage 21 so as to bring the ring pin point 29 in close relationship with the annular firing anvil 22. tails of the mechanism for operating the firing pin are fully described and disclosed in the above-identied copending application.

Means in addition to the head portion of the breech bolt for closing the annulus'24 comprises an arcuate or substantially semicircular ange 3B which partially circumscribes the outer edge of the bolt and projects at substantially right angles to the face 3l thereof. This flange 3B is of a thickness, as seen in Fig. 2, substantially equal to the height of the annulus 24. Consequently, as the bolt is advanced to breech-closing position, the flange 3i! will be thrust into the annulus 24 thereby substantially closing the annulus from the atmosphere. The annulus thus becomes a substantially closed passage bounded by Vthe adjacent surfaces of the barrel, the receiver Il, the face of the ange 30 and thelower portion of the bolt head 26.

The cartridge 3?. may be loaded into the barrel chamber in any-well known manner, as for example, manually, as in a single-shot firearm, or automatically, as accomplished by the loading mechanisms of repeating iirearms. The cartridge is forced into the barrel chamber I9 by the advancing bolt head 26 until the rim of the cartridge is iirmly seated on the firing anvil 22 with the periphery 34 of the cartridge rim in contact with the substantially vertical walls 2| of the counterbore. At this time, the head of the cartridge is substantially flush with the rear end of the barrel chamber so that the face 3l of the bolt, which has been advanced and locked in breech-closing position, abuts thereon in the manner shown in Fig. 2.

The arcuate flange 30 of the bolt projects into the annulus 24 so as to form a substantially closed passage circumscribing a major portion of the barrel, the remaining or lower portion of the annulus being closed by the adjacent surface of the bolt head 26. The gun may be fired by pulling the trigger so as to release the firing pin plunger 28 and permit the firing pin point 29 to strike forcibly against the rim of the cartridge.

It is clear that the rim of the cartridge is not only supported, but is also enclosed substantially on all sides by the walls of the chamber counter-- bore, which construction has been found in actual practice to eliminate approximately 90% of the burst cartridge heads heretofore experienced.

Although the theory which accounts for the occurrence of burst heads in previous types of iirearrns is not exactly known, it seems probable that inasmuch as the rim of the cartridge-was squeezed or crushed between the lrear face of the barrel chamber and the face of the bolt and as there was no reinforcement of any kind provided for the periphery of the cartridge rim, the periphery became aipoint of relative Weakness compared to other encased or supported parts of the Vcartridge head, and hence would rupture when subjected to the pressures developed incident to the explosion taking place in the cartridge.

It will beV evident, however, that the embodi- 'the adjacent surfaces of the chamber and bolt and are often thrown back into the eyes of the shooter. However, by the construction shown, these gases will pass out into the closed annulus r24 which directs the gases down to the vent or port 25 from which they escape harmlessly at a point remote from the shooters eyes.

Since the invention is believed to provide a novel and improved rimiire firearm, it is not limited to the particular construction shown and described herein, but is to be construed as covering all equivalent devices falling within the scope of the appended claims.

What is claimed is:

l. In a bolt-action firearm for rimre cartridges, the combination comprising a receiver, a breech bolt reciprocably mounted in said receiver and a chambered barrel secured in said receiver, said barrel comprising an end portion of exteriorly reduced diameter adjacent the chamber mouth adapted withY said lreceiver to form an annulus the upper half of which is closed from the atmosphere by said bolt when in chamber-closing position, said receiver having a port opening into the lower half of said annulus and constructed and arranged to exhaust gases therefrom, and a counterbore in the chamber mouth comprising a curvilinear shoulder for seating the cartridge rim when the bolt is in chamber-closing position.

2. In a bolt-action firearm for rimiire cartridges, the combination comprising a receiver. a breech bolt reciprocably mounted in said receiver, said bolt having a face provided on its upper edge with a semi-circular iiange and a chamberedbarrel secured in said receiver, said barrel comprising an end portion of exteriorly reduced diameter adjacent the chamber mouth adapted with said receiver to form an annulus the upper half of which is closed from the atmosphere by said semicircular flange when said bolt is in chamber-closing position, said receiver having a port opening into the lower half of said annulus to exhaust sparkstherefrom, a, counterbore in the chamber mouth Vadapted to seat the cartridge rim when the bolt is in chamber-ciosing position, and a iiring pin in said bolt adapted to pinch a portion of the cartridge rim against the seat.

3. In a bolt-action rearm for rimiire cartridges, the combination comprising a receiver, a breech bolt reciprocably mounted in said'receiver, said bolt having a face provided in its upper edge `with a semicircular iiange and a chambered barrel secured in Vsaid receiver, said barrel comprising an end portion yci? Vexteriorly reduced diameter adjacent `the chamber mouthVV adapted lwith said receiver to 4form an annulus, said semicircular iiangeV being constructed and arranged to close the upper half of said annulus from the atmosphere when said bolt is in chamber-closing position, saidreceiver having a port opening into .theV lower half of said annulus and lie the exteriorly reduced end portion of said barrel and to close the upper half of said annulus from the atmosphere when said bolt is in chamber-closing position, said receiver insert having a spark exhaust port opening at its upper end into the lower half of said annulus and exhausting at its lower end into said receiver, and a counterbore in the chamber mouth having a ring anvil adapted to seat the cartridge rim when 10 the bolt is in chamber-closing position.

CRAWFORD C. LOOMIS. 

